Cylinder locks are well known in the art and widely used in many industries and products for achieving an inexpensive locking system. In typical constructions, cylinder locks are manufactured with spring biased pins or spring biased plates or wafers forming the tumblers for controlling the opening and closing of the lock.
These locks are usually constructed for being key-operated, with the configuration of the key being controlled by the tumbler construction. Once a matching key is inserted into the lock assembly, the spring biased tumblers are moved from a locked position into a released position, allowing the cylinder to rotate in its associated housing. In this way, the lock is opened and the desired locking and unlocking functions are activated.
In most prior art lock constructions, the cylinder comprises an elongated, closed, one-piece construction and is mounted in a cooperating housing which incorporates at least one axially elongated slot or groove. In addition, the cylinder incorporates a plurality of spring biased tumblers either in the form of plates, wafers, or pins, which are constructed for being normally biased into the slot or groove of the housing. In this way, the cylinder is in a locked position when the tumblers are within the slot and the unlocked position when the tumblers are removed from the slot by having the key associated with the particular lock inserted therein.
In the construction of cylinder locks incorporating a plurality of wafers or plates as the tumblers, each wafer or plate comprises a generally rectangular shape incorporating a uniquely dimensioned slot formed therein which is positioned for receiving the key when inserted into the lock assembly. In addition, each wafer or plate comprises a locking fin member which is spring biased to be maintained in the slot or groove of the housing. However, when the appropriate key is inserted through the rectangular slots of the wafer or plate, the plate is moved against the spring forces in a manner which removes the locking fin from the groove, thereby enabling the cylinder to rotate relative to the housing.
Although this basic construction has been widely employed and accepted for use in numerous products, a substantial expense is incurred in manufacturing these locks, due to the tedious and difficult assembly required for constructing and positioning the wafers or plates forming the tumblers for the lock assembly. In most constructions, the cylinder is mass produced with wafer or plate receiving slots or wards formed therein. However, manual assembly is required to insert and set the wafers or plates in the cylinder with the biasing springs to assure that the wafers/plates function as tumblers to control the operation of the lock.
Once the plate tumblers are inserted into the cylinder and prior to insertion of the cylinder into the housing, the spring forces tend to force the plate/tumblers out of the slots. Consequently, holding means are required in order to prevent dislodgement of the plate tumblers. Typically, a separate holding member or a cylinder construction is employed which retains the plate tumblers in position while still enabling the plate to function in its intended manner when assembled in the housing.
One problem, which is frequently encountered during the assembly of the plate tumblers, occurs when plate tumblers are dislodged from the cylinder after insertion therein. When this problem occurs, particularly when two or more tumblers are dislodged, the plate tumblers must be properly reinserted into the cylinder in the correct order. If incorrect reassembly is made, the key constructed for opening the lock by positioning the tumblers in the slot-dislodged position will not function.
A further problem and substantial expense is also incurred whenever a lock assembly is to be changed, by having a new tumbler arrangement installed for requiring a new key configuration to be used to open the lock. In such instances, either the entire lock assembly is removed and replaced, or the wafers/plates forming the tumblers are changed so that a new combination is established and a new key is required. However, in any such change, manual effort and substantial expenses are incurred.
Therefore, it is a principal object of the present invention to provide a cylinder lock construction which eliminates the need for manual assembly of plate tumblers during assembly of the lock.
Another object of the present invention is to provide a cylinder lock construction having the characteristic features described above which is quickly and easily assembled without requiring specialized training.
Another object of the present mention is to provide a cylinder lock construction having the characteristic features described above which completely eliminates any possibility of tumbler dislodgement during the assembly process.
Another object of the present invention is to provide a cylinder lock construction having the characteristic features described above which enables rapid, trouble-free changing of a tumbler combination without substantial expense or difficulty.
Other and more specific objects will in part be obvious and will in part appear hereinafter.